Under the Köppen Climate Classification climate classification, "dry-summer subtropical" climates are often referred to as "Mediterranean". This climate zone has an an average temperature above 10°C (50°F) in their warmest months, and an average in the coldest between 18 to -3°C (64 to 27°F). Summers tend to be dry with less than one-third that of the wettest winter month, and with less than 30mm (1.18 in) of precipitation in a summer month. Many of the regions with Mediterranean climates have relatively mild winters and very warm summers.

The Köppen Climate Classification subtype for this climate is "Csa". (Mediterran Climate).

The average temperature for the year in Stellenbosch is 60.0°F (15.6°C). The warmest month, on average, is February with an average temperature of 69.0°F (20.6°C). The coolest month on average is July, with an average temperature of 51.0°F (10.6°C).

The average amount of precipitation for the year in Stellenbosch is 36.6" (929.6 mm). The month with the most precipitation on average is June with 6.6" (167.6 mm) of precipitation. The month with the least precipitation on average is January with an average of 0.9" (22.9 mm).